Retainer for oscillating moistening roll shaft



Oct. 30, 1951 E. J. JANKE 2,573,572

RETAINER FOR OSCILLATING MOISTENING ROLL SHAFT Filed June 14, 1949 Patented Oct. 36, 1951 umrso STATES PATENT OFFICE RETAINER FQ-R OSCILLATING MQISTENING ROLL SHAFT Edward J, J anlge, Cleveland, Ohio, assignor to AddressographeMultigraph Corporation, (llevee land, O o a rnor n f D lawa Application June 14, 1949, Serial No. 99,076

6 Claims (Cl- 387E211),

This invention relates to retaining; devicesv and more particularly to a retaining device adapted for u n a r ary offset litho r phic printing machine wherein a lithographic master, from which impressions are to be made, is mgunted lude the ink from adh rin t anythin othe I than the ink-receptive ima e.v

It has been customary to supply ink to the master in printing machines of the aforesaid character from a fountain, into which the in}; is

d ed. hroug a series of olle s of which ne perates in the fountain to p ll; up .111s therefrom. Usually a transfer roller is provided in the train in spaced relation with th fguutain roller and still another roller is, inter o ed between the fountain an transfer rollers and Q1 erates to move fro periph ral co tact from on or such rollers int periph ral c ntact with th othen such a m v b e roller bein commonly known as a ductor roller. Th tra n of roller that is effective to Supply the ink to the image also includes one or more rollers which are disp sed such pos i as o rol ov r the mas be ri the ima e as i ma e com s into contest w th th e o le s. n he our e of ohorotlor o the mach n Th ro l s which e thus offe ti to sup l 1 1s to e ima s o e master are kn w s f m rol ers. A t ain of rollers 9 the afo esa d cha a so sually include therein. int rm e e oc r ro er and th rolle o ro s, a r ler t whi h a l .ituoinal or axial s. W ll s a otar m vement i impor d and such rolle s ommonly ref r e to s sci a n d s buto r l e z th pur- Pose o his roller be n to in ure unifo m v l sti n f the k al n the periphery of th roll rs nd. pecial a on e peri ery of the o m roller o oll s,-

e repellent so t o i sup l d to the unlmass p r i s of the m s e hrou h or; ar-

rs se n m l o he l s sore y Thus, his arrang ment udes at least on ro er whio s disp sed n pos t o o ri e on th lrfaoe of the lithographic master as t moves thereby in he opera ion o the meohirle. o

rol r al being kno as a, o m o l r: in eds itiorr to s on a for ro l t e arrangement or ain sup l n r e e t to th m tor ne tornarily includes a fountain into whiqll the re,- pellent solution may be introduced and also a r ll r o r so i os io o c u repel en from the f un in th s o l r b hs'khowh as t e ounta n roller. he repelle t urely orrangement also usually includes a ductgr rgller which is effective to transfer repellent from the f u tain ro t a d stribu i r e wh ch is all dispose in p r phera ensasemen with t e for o l r r r rs o su p e repellen s lu o th eto! I me n rlo s, suoh o (l st bllti s. roller s ar ed for merel ro ary m em n t n her ins anc s i fo n t e s b e to mport a l n itucllnal or ax l as W a a otati g m em n to o distributing roller since so to do insures unifolfm distribution of the repellent esnsolally over the f m ol r or r lle s- Wh re suoh. a d stributing roller is arranged to have longitudinal as well as rotative movement imparted thereto, it is commonly known as an oscillating distributor roller and it corresponds in function and arrangement to th oscillating distributor roller customarily employed in an ink supply arrangement as described hereinabove.

spe iall in ar ang men s o the aforesaid har t f p lying re l ent to s l h gra hi master it has been found to be advantageous to insure that the distributing roller remainsin firm eng ge ent th t orm lle o as t insure uniform distribution of the repellent solution over and about the'surfaee of the form roller. Moreover, it is advantageous in printing machines of the aforesaid character to enable u a d str n r l to be e d l remove fro t e ac ine In m m ch nes. of th aforesaid kind it is necessary to arrange for sed o s mo a f e distr b t n rol e sin in such machin s t e d tr ut rollers a e mounted abo an o rt e. form rol o s- 'R moral of t e or o lers f m ime to i us a y ece s r o t s custom y to ovid a moisture absorbent felt, such as molletin, 9n he p i er of u h a roller and s loh e so ing s m ved nd r placed from me to t m so s to u e t at o o n re rod loti os will b produced in the printing rnaqhille.

In w o th f re oing! it t e ohieot o m e on t afford a n l r angemen t a i l b e leo to re a n a dis rl outlhe roller 0 th fo esa c ra t r o the li e firm bu y ding ngagement with. another rol r, such as a form roller in an ink or repellent train. So to do eliminates undesired separation of the rollers and precludes bouncing of one roller on the other. roller, any such bouncing having been found to be particularly disadvantageous in the repellent train of a printing machine of the aforesaid character.

Other objects of the invention are to retain a distributing roller or the like in firm but yielding contact with another roller and yet enable the retained roller to be expeditiously removed from the machine when and if desired; and to so retain such a roller by resort to an arrangement so fixed in retaining position as to insure against accidental misplacement thereof.

Still other objects are to utilize an arrangement that may be permanently connected to the ma-. chine and which may be effective to limit longitudinal or axial movement of a distributor roller or the like relative to the portions in the machine in: which the roller is mounted; to enable the firm but yieldable engagement between rollersof the'aforesaid character to be expeditiously adjus'ted when and if desired; and to enable a portion of a roller retaining arrangement of the aforesaid character to be moved toand retained in an ineffective position where such portion will not interfere with removal of the retained roller from the machine.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawing which, by way of illustration, show preferred embodiments of the present invention and the principle thereof and what I now consider to be the best mode of applying that principle. Other embodiment of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims. In the drawing:

Fig. lis a fragmentary perspective view of an offset lithographic printing machine in which my invention has been incorporated;

Fig. 2 i another fragmentary perspective view,

.drawn to a scale larger than Fig. l, and showing the retaining element of my novel roller retaining arrangement in the effective roller retaining position thereof i Fig. 3 is a fragmentary side elevational view whereinthe retaining element of my roller reitaining arrangement is shown in the ineffective position thereof F g. 4jis a vertical sectional detail vi w tak .isubstantially on the line 4 a on Fig. '3 but ,wherein the retaining element of the roller retaining arrangement is shown in the effective position thereof v Fig. 5 is a horizontal sectional view taken substantially on the line 5-5 on Fig. 4; and

Fig. 6 is a view similar to Fig. 4 but showing a modified form of my arrangement and wherein the various elements of my arrangement are shown in elevation.

The embodimentof my invention shown in Figs. 1 to 5 of the accompanying drawing is illustrated in association with an offset lithographic printing machine of the kind disclosed in Morse Patent No. 2,065,535, patented December 29, 1936,

, andparticularly the arrangement for sup-plying chine as illustrated includes a framegenerally indicated by F having brackets l9 and I I mounted thereon which afford a support for the repellent supply arrangement. This arrangement includes a trough l3 into which a supply of liquid repellent is introduced either manually from time to time or through an automatic source of supply such as that disclosed in aforesaid Patent No. 2,065,535. A roller I4 is mounted for rotative movement in position to pick up from the trough [3 liquid repellent introduced thereinto and a rotatable and movable ductor roller I5 is suitably supported in the machine to be bodily movable, in a reciprocatory manner, between, and so as to have alternate peripheral contact with, the fountain roller l4 and an oscillating distributing roller [6, one means suitable for efiecting such reciprocatory movement of the ductor roller 15 being disclosed in'the aforesaid patent. The distributing roller I6 is mounted above and in position to have peripheral engagement with a form roller I! mounted so as to roll upon the surface of a lithographic master in the course of operation of the printing machine. The form roller H, as in the instance of other elements referred to hereinabove, is in the nature of that disclosed in aforesaid patent and is set in rotation in the manner disclosed in that patent.

As is customary in the art, the form roller [1 desirably has a removable moisture absorbent felt, such as molletin, on the periphery thereof which is usually in the nature of a sleeve and which sometimes may have a seam running longitudinal thereof. I have observed, where such a covering is included on a form roller as IT and the covering has a longitudinal seam therein, that if the distributing roller is not held in firm but yielding engagement with the form roller in the course of rotation of the rollers, the distributing roller may be forced upwardly away from the form roller as the seam passes the distributing roller and after the seam is once passed the distributing roller it returns to engagement with the normal periphery of the form roller IT. This, in some instances, has resulted in the distributing roller bouncing on the form roller and this has been found to be objectionable in printing machines of the kind in which my invention is embodied. I have, therefore, provided an arrangement for maintaining the distributing roller [6 in firm but yielding engagement with the form roller I 7.

In aforesaid Patent No. 2,065,535 the distributing roller that contacts the form roller is described as having a layer of felt or more moisture absorbing material, such as molletin, secured thereon. However, in an instance such as the present, where the distributing roller is to have longitudinal as well as rotary movement imparted thereto, it has been found to be advantageous to eliminate such a covering so that in the present instance the periphery of the distributing roller l6, that is to engage the form roller I1 and be engaged by the ductor roller I5, is preferably rubber or other resilient but non-absorptive materia or insome instances metallic.

In the present instance rotary movement is imparted to the roller It by the peripheral engagement thereof with the form roller I! which, as is customary in the art, is positively driven through the intermediary of gears and the like in timed relation with other operative parts in the machine including the drum on which the lithographic master'is mounted. Longitudinal movement may be imparted to a distributing gem-we 5 roller as it in different ways but in the present instance the assembly of which the roller it is 'a partincludes a non-rotatable shaft I8 and 'an' arrangement such as that disclosed in Morse Patent No. 2,006,364, patented July 2, 1935, is utilized to impart the desired longitudinal movement. Thus, a hub as |9 is fast to the shaft 3- inwardly of each end thereof. A cam groove (not shown) is provided in the periphery of such a hub. The peripheral portion of the shaft l8 is'afforded by a shell or sleeve mounted for rotative and slidable movement on the hubs as I9. The shell has a cam follower (not shown) in the form of a roller or the like, mounted interiorly thereof and this follower rides in the cam groove provided in the hub as aforesaid. The configuration of the cam groove is such that as the cam roller or the like travel-s therethrough, a reciprocatory motion is imparted to the periphery of the distributing roller It in the course of rota-tive movement thereof. It will be understood that resort may be had to arrangements other than the foregoing to impart the reciprocatory as well as rota-tive movement to at least the peripheral portion of a distributing roller as 16 since such means are not a part of my present invention;

'Where, as in the present instance, the oscillatory distributing roll assembly includes a stationary shaft as |8, it is advantageous to provide a recess as 20 in each of the brackets ii} and H in such positions that when the outwardly extending end portions of the shaft as are disposed in such recesses, the periphery of the distributingroller as It will be disposed in position to ride on aform roller as I! and also in position to be engaged by a ductor roller as at the end of reciprocatory movement of this latter roller in one direction. Portions at each end of the shaft 18 are cut away along chords to afford a flattened end portion as 2| at each end of the shaft. These flattened end portions have shoulders as 22 at the inner ends thereof and, when the flattened end portions as 2| are respectively disposed in the recesses as 23 in the brackets as It and ll, these shoulders respectively engage the adjacent portions of the inner faces of the brackets as Hi and H and thereby the shaft as It is held against longitudinal or axial movement in the machine.

It has been explained hereinabove that it is desirable to maintain a distributing roller as H5 in firm but yielding engagement with a form roller as IT. Moreover, especially when a distributing roller as I6 is to have reciprocatory nature that a portion thereof may be moved to and retained in an ineffective position so as to thereby enable installation in, or removal of, a

distributing roller as I6 into and from the machine when and if desired. In Figs. 2 to 5 of the drawing I have shown the arrangement which is provided for the end of the shaft l8 that is disposed in the recess 29 afforded in the bracket l and it will be understood that, in the present instance, a similar arrangement is provided for association with the end of the shaft I8 mounted in the recess 20 in the bracket The arrangement illustrated in Figs. 2 to.

"includes an annular post member 23 which is screw threaded at. one end thereof. as indicated alt-2'4. An adjusting nut 34,- explainedhereinafter, is mounted for movement along the screw threads 24 and a cap nut 25- cooperates with the screw threads 24 to be securedon the adjacent end of the post 23. The post is also screw threaded-at the other end thereof so that it may bethreaded into th'etapped opening 2-? provided in the lower wall of'the recess 26. In the present instance the" opening 27 isylocated substantially midway between the sidewalls of the recess '28 and also substantially midway b'etweenthe opposite faces of the bracket |fi.- Thepost 2'3is firmly mounted in the tappedopening 21 to insure against undesired displacement thereof.

A retaining element, generally indicated by 23, has a bore 29' extending therethroug-h which is of a diameter slightly greater than the diameter of the post 23 so that the element 28- is freely movable along the post. The retaining element has "an annular collar portion St at the upper end thereof, the periphery of which is preferably knurled, The body 3| of the retaining-element, below the collar portion 36 thereof, is of'a' length equal'to the diameter of such collar portion but is of restricted width relative to such diameter and this body includes opposed fiat surfaces or faces 32 so the body 3| is, in effect, elongated but of restricted Width. This restricted width of the body 3|, enables it to freely pass into a recess as 29, but the length of the body 3| is greater than thewidth of the recess 2% so as to enable the retaining element" to b'e'disposed' and retained in an inefiective position, as will be described.

A spring 33 is disposed about the post 2 3"between the adjusting nut 34 and the collar portion 35) and is effective to urge the retaining element 28" downwardly on the post 23 when the threaded portion 26' has been fast in the tapped openingv 2T.

When it is desired to mount the shaft |8' of the roller assembly It in the machine, the retaining element 28 is moved upwardly along the body of the post 23 against the effect of the spring 33 and the retaining element is also so rotated into position with respect to the body of the post that one of the flat surfaces 32 thereon is disposed to face inwardly of. the machine and be in at least substantially parallel. relation with the adjacent end of the shaft as |-8 that is tobe disposed in the recess as 20 in which the post is mounted. When the retaining element is so oriented relative to. the post 23,, the fiat surfaces 32 thereof will be in substantially parallel relation with the side walls of the bracket as If]. Whenthe flat surfaces: 32 are this position, the end portions of the body 3| extend over the free edges of the marginal portions of the side walls of the recess Fig. 3. When a retaining element as 28 is disposed in this just described position, it is retained in an. ineffective position and the adjacent end portion as 2 of a shaft as I8 may be freely moved inwardly and outwardly of the recess as 20 adapted to receive the same since the body portion 3| will be out of alignment; with the end portion as 2|.

When the end portionsas 2| have been introduced into the recesses at a time when the retaining elements are held in the aforesaid ineffective positions thereof, the periphery of the roller l6 engages and rests upon the periphery of the form roller When. this occurs, one of the fiat faces of the adjacent end portion 2| of the shaft as |8 may rest upon the lower wall of the recess 20 dependent upon the relation established among the various parts. In some instances, however, the lower of the fiat faces of the end portion 2| will be disposed in spaced relation with the lower wall of the recess 20 in which the end portion is disposed. After the end portions '2] of the shaft I8 have been arranged in the recesses 20 in the just described manner, the retaining elements as 28 may be raised against the effect of the springs 33 and the element is then rotated so as to present the fiat faces 32 in substantially parallel re lation with the side walls of the recess 20 in which the retaining element is mounted. Thereupon the body 3| of the retaining element 28 is free to enter the recess and when the body 3| is inserted into the recess and freed to the effect of the spring 33, one end portion thereof comes to rest upon one of the fiat faces on the end portion 2| of the shaft I8. When the retaining elements as 28 are thus disposed in effective position so as to be engaged with the adjacent end portions 2| of the shaft It, the springs 33 are effective to urge the roller 5 into firm but yielding en- V gagement with the form roller as In such circumstances, the nut 34 may be moved along the screw threaded portion 24 of the post as 23 so as to thereby vary the length and, therefore, the effectiveness of the adjacent spring as 33. Each nut as 34 is moved into such an adjusted position as to cause the associated spring as 33 to exert the proper degree of pressure on the roller as l6. Desirably the pressure thus exerted on the roller 6 is sufficient to hold the periphery of this roller-I6 in firm but yielding engagement with the periphery of the form roller as I! and such pressure is also desirably sufiicient to insure against bouncing of the roller l6 relative to the roller 7 7 When it is desired to' remove an oscillating distributor roller assembly as Hi from the machine, each of the retaining elements as 28 is moved upwardly against the effect of the springs 33 and each element is rotated so as to be in the position of the retaining element 28 shown in Fig. 3 where the retaining'element is disposed and retained in an ineffective and out-of-theway position. Since the adjacent free end of the adjacent end portion 2| of the shaft is out of alignment the adjacent flat face 32 of the cooperating retaining element once the element is disposed and retained in its aforesaid ineffective position, the shaft as [8 may be freely moved into or out of the recesses as 20.

The modified formpf my retaining arrangement shown in Fig. 6' is quite similar tothat shown in Figs. 2 to 5 and in those instances where the elements shown in Fig. 6 correspond to those shown in Figs. 2 to 5, the reference character employed 'in Figs. 2 to 5' is applied to the corresponding element in Fig. 6 but the suffix A is added thereto. The modified form of my'arrangement shown inFig. 6 is one which is effective to not only maintain a roller as WA in firm but yielding engagement with a form-roller but this retaining arrangement is also so constructed as to enable it to be employed to limit endwise or axial movement of the-shaft as ISA.

T us end. and as shown in Fig. 6. thelower end of the post member 23A is enlarged as indicated at 35 so as to be of a diameter greater than that of the remaining extent of the post member. As in the instance of the post member 23A the lower end of the enlarged portion 35 is screw threaded, as indicated at 26A, so as to enable the same to be firmly mounted in a tapped opening as 21A. The diameter of the enlarged portion 35 and the end portion 2|A of the shaft as |8A are so related one to the other that, when the free end of the end portion 2|A is engaged with the periphery of the enlarged portion 35, the shoulder 22A will be held in spaced relation with the adjacent surface of the bracket as |0A in which the recess as 20A is provided. Thus, since the free end of the end portion 2|A engages the periphery of the enlarged portion 35 of the post member 23A, this post member is effective to limit axial movement of the shaft as 18A in one direction and, when an arrangementsuch as that just described is provided at the other end of the shaft as IBA, thisarrangement is effective to hold the shaft as |8A against movement in the other longitudinal or axial direction.

As in the instance of the retaining element 28, when the retaining element 28A is introduced into the recess 20A and freed to the effectof the spring 33A, it is effective to hold the roller as |6A in firm but yielding engagement with a form roller or the like. Moreover, when the retaining element as 28A is raised against the effect of the spring as 33A and is disposed and retained in the ineffective position thereof, which corresponds to the ineffective position of the retaining element 28 as shown in Fig. 3, then because of the diameter of the enlarged portion 35 and the restricted width of the body 3|A of the retaining element 28A, the adjacent end portion 2 IA of the shaft as 18A may be freely lifted out of the recess as 20A.

While I have described each form of my retaining arrangement as being associated with an oscillating distributor roller in an arrangement for supplying repellent to a lithographic master mounted on the master drum or cylinder of a lithographic printing machine, it will be understood that either illustrated form of my retaining arrangement, or other modification thereof, may be advantageously employed to retain a distributing roller of this character in operative position in a machine whether or not the roller is arranged to have longitudinal or axial movement imparted thereto as well as rotative movement. Moreover, if desired, either illustrated form of my retaining arrangement, or other modification thereof, may be used in association With a distributing roller included in an arrangement for supplying ink to a lithographic master mounted on the master drum or cylinder in a lithographic printing machine. Furthermore, various forms of the arrangement which I have provided may be used in association with any roller that is to .be mounted in recesses afforded in a bracket or machine frame and especially where it is desirable that the roller be capable of removal and installation in the machine from time to time. Yet further, in many instances, my novel retaining element may be associated in the above described manner with but one end of a shaft and in such circumstances the other end of the shaft may be retained in op-.

erative position in any desired and appropriate manner.

It will be manifest from the foregoing description that the retaining arrangement which. I

v ,9 have provided enables the hereinabove and related objects of this invention to be realized. Hence, while I have illustrated and described preferred embodiments of my invention, it is to be understood that these are capable of variation and modification and I, therefore, do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

1. In an apparatus of the character described including a frame member having a recess therein, a roller including a shaft end disposed in said recess to be capable of movement inwardly and outwardly of the recess, a retaining arrangement including a post member fast in the bottom wall of said recess, a retaining element mounted on said post member for movement therealong and for rotation thereabout, said retaining element including a shaft engaging part of restricted width to enable such part to pass into the recess and engage the shaft end therein, and yieldable means eifective on'said retaining element to urge the same along the post member and its shaft engaging part into the recess to engage the shaft end disposed in said recess, said shaft engaging part being of suflicientlength relatively to the width of said recess so that when the retaining element is moved upwardly against the effect of 30 the yieldable means and rotated about said post member at least a portion of the lower edge of such shaft engaging part may be disposed above and rested on the free edge of the marginal portion along at least one edge of the recess, the 35 yieldable means being effective on said retaining element to retain it in engagement with the free edge of such marginal part, the restricted width of said shaft engaging part being such as to enable the shaft end to be moved out of or into said recess when the lower edge of said shaft engaging part is engaged as aforesaid with the free edge of said marginal portion.

2. In an apparatus of the character described including a frame member having a recess therein, a roller including a shaft end disposed in said recess to be capable of movement inwardy and outwardly of the recess, a retaining element including a post member fast in the bottom wall of said recess and including an enlarged part disposed to be effective to limit axial movement of the roller shaft in one direction, a retaining element mounted on said post member for movement therealong and for rotation thereabout, said retaining element including a shaft engaging part of restricted width to enable such part to pass into the recess and engage the shaft end therein, and yieldable means effective on said retaining element to urge the same along the post member and its shaft engaging part into the recess to engage the periphery of the shaft end disposed in said recess, said shaft engaging part being of sufficient length relatively to the width of said recess so that when the retaining element is moved upwardly against the effect of the yieldable means and rotated about said post member at least a portion of the lower edge of such shaft engaging part may be disposed above and rested on the free edge of the marginal portion along at least one edge of the recess, the yieldable means being effective on said retaining element to retain it in engagement with the free edge of such marginal part, the restricted width of said part being such as to enable the shaft end to be moved out of or into said recess when the lower edge 5 in, a roller including a shaft end disposed in said recess to be capable of movement inwardly and outwardlyof the recess, a sl'raftv retaining arrangement including a post member having means thereon at one end thereof directly and rigidly securing the same in the bottom wall of said re! cess, a retaining element mounted for movement along and for rotation about said post member, said retaining element including a shaft engage ing part of restricted width to enable such part to pass into the recess and engage the shaft end,

and yieldable means effective on said retaining element to urge the same along the post member and its shaft engaging part into the recess in which the post member is secured, the retaining element being of sufficient length relatively 'to the width of the recess, and the shaft engaging part so related to the width of the recess that when the retaining element is moved longitudinally against the pressure of said yieldable means to withdraw the shaft engaging part out of the recess and is then partially rotated to poe sition its shaft engaging part out of registering alignment with the recess, the shaft engaging part will engage upon the free edge of a marginal portion of the recess, and the retaining element Will be held in elevated position to enable'm'ovement of the shaft end out of and into the recess.

4. In an apparatus of the character described including a frame member having a recess therein, a roller including a shaft end disposed in said recess to be capable of movement inwardly and outwardly of the recess, a shaft retaining arrangement including a post member having means thereon at one end thereof directly and rigidly securing the same in the bottom wall of said recess, a retaining element mounted for movement along and for rotation about said post member, said retaining element including a shaft engaging part of restricted width to enable such part to pass into the recess and engage the shaft end, and yieldable means effective on said retaining element to urge the same along the post member and its shaft engaging part into the recess in which the post member is secured, the retaining element being of sufficient length relatively to the width of the recess, and the shaft engaging part so related to the width of the recess that when the retaining element is moved longitudinally against the pressure of said yieidable means to withdraw the shaft engaging part out of the recess and is then partially rotated to position its shaft engaging part out of registering alignment with the recess, the shaft engaging part will engage upon the free edge of a marginal portion of the recess, and the retaining element will be held in elevated position to enable movement of the shaft end out of and into the recess, and means on said post member operative to vary the effectiveness of said yielding means.

5. In an apparatus of the character described including a frame member having a recess therein, the bottom wall of said recess being provided with a tapped opening therein, a roller including a shaft end disposed in said recess to be capable of movement inwardly and outwardly of the recess, a shaft retaining arrangement including a post member having a screw threaded part at one end thereof mounted in said tapped opening in the bottom wall of the recess, a retaining element mounted for movement along and for rc- 7 5 tation about said post member, said retaining ele- '11 ment including a shaft engaging part of restricted width to enable such part to pass into the recess and engage the shaft end, and yieldable means effective on said retaining element to urge the same along the post member and its shaft engaging part into the recess in which the post member is secured, the retaining element being of sufficient length relatively to the width of the recess, and the shaft engaging part so related to the width of the recess that when the retaining element is moved longitudinally against the pressure of said yieldable means to withdraw the shaft engaging part out of the reces and is then partially rotated to position its shaft engaging part out of registering alignment with the recess, the shaft engaging part will engage upon the free edge of a marginal portion of the recess, and the retaining element will be held in elevated position to enable movement of the shaft end out of and into the recess.

6. In an apparatus of the character described including a frame member provided with a recess therein, a roller including a shaft having one end thereof removably disposed in said recess, and means for retaining said shaft end within said recess including a post member extending outwardly from the bottom wall of the recess, said post member being rigidly secured at its lower end directly to the bottom wall of the recess, a retaining element mounted on said post member 12 for movement along the same and for rotary movement thereabout, said retaining element having an elongated shaft'eng'aging part of a width to permit the same to pass into said recess and engage said shaft end, yieldable means effective on said retaining element to urge the same inwardly along the post member and its shaft engaging part into said recess in engagement with said shaft end, and the shaft end engaging part of the retaining element being of sufiicient length relatively to the width'of the recess to engage upon the free edges of the side walls of the recess when the retaining element is moved longitudinally against the pressure of said yieldable means to withdraw its shaft engaging REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Mitchell Nov. 18, 1947 Number 

